Performances of As(V) adsorption of calcined (250 °C) synthetic iron(III)–aluminum(III) mixed oxide in the presence of some groundwater occurring ions

Agglomerated iron(III)–aluminum(III) mixed oxide nanoparticles (NIAO) were investigated for their As(V) adsorption performances in the presence/absence of some ions occurring in groundwater. NIAO sample calcined at 250 °C (NIAO-250) showed highest As(V) adsorption efficiency at pH = 7.0 (±0.1) and 30 °C. The pseudo-second order and the Langmuir isotherm models described, respectively, the kinetic and equilibrium As(V) adsorption data of NIAO-250 very well. The Langmuir monolayer capacity of As(V) adsorption by NIAO-250 estimated in the absence of any other ion (54.55 ± 2.04 mg g−1) was about 15–35% higher than that in the presence of tested ions occurring in groundwater, implying adverse influence on the removal reaction. Adsorption reactions were endothermic and spontaneous, which took place with increasing entropy (ΔS° = +0.072 to +0.158 kJ mol−1 K−1). Spontaneous nature of reactions increased with increasing temperature. Low regeneration (∼40%) of As(V) adsorbed NIAO-250 by 2.0 M NaOH solution and other supporting evidences suggested that As(V) was bound to NIAO-250 surface by chemical interaction.

► Novel synthesis method of nano structured iron(III)–aluminum(III) mixed oxide.
► As(V) adsorption investigated in the presence of some ground occurring ions.
► Decrease of As(V) adsorption efficiency in the presence of some groundwater occurring ions.
► High As(V) adsorption by the synthetic material occurring by chemisorption.
► Novel material can be used for filtration of high As(V) from contaminated water.